1. Field of the Invention
This invention relates to apparatus used in the dispensing of fast-setting multi-component adhesives, particularly medical adhesives, and more specifically, to various embodiments of a mixing device for mixing a multi-part polymer tissue adhesive, to a method for fabricating the same, to a dispenser apparatus incorporating the mixing device and to a method for fabricating the dispenser apparatus.
2. Description of the Prior Art
A fast-setting two-component adhesive is an adhesive compound that cures within seconds of the components being mixed together. Such fast-setting two-component adhesives have many applications, including use as tissue adhesives for a number of potential medical applications. Such potential medical applications include closing topical wounds, adhering synthetic onlays or inlays to the cornea, delivering drugs, providing anti-adhesion barriers to prevent post-surgical adhesions, and supplementing or replacing sutures or staples in internal surgical procedures. To be suitable for medical applications such tissue adhesives must be fast-curing, have good mechanical strength, be able to bind to the underlying tissue and pose no risk of viral infection. It is particularly important for internal applications that such tissue adhesives not release toxic degradation products.
The components of such fast-setting two-component adhesives must be mixed at the site of application or immediately (i.e., typically within a few seconds) before application. Conventional static mixers have been employed to mix the two components together as the adhesive is applied to the tissue. These conventional static mixers typically employ a serpentine passage. The mixing action occurs within the serpentine passage before the adhesive exits the mixing passage. Representative of such conventional static mixer are those devices sold by Med Mix Systems AG, Rotkreuz, Switzerland and Mix Tek System LLC, New York, N.Y.
U.S. Pat. No. 5,595,712, assigned to the assignee of the present invention, also discloses a static mixing device employing a serpentine passage within a planar structure.
These prior art static mixers are believed disadvantageous for use in any medical application which requires intermittent application of adhesive. If flow of the adhesive through the mixer is interrupted, even momentarily, the mixed components rapidly increase in viscosity. This increase in viscosity, known as gelling, may occur so rapidly that the mixer passage becomes clogged, thus preventing the resumption of flow of the adhesive.
Besides the static mixers previously described, dynamic mixers such as powered impellers and magnetic stir bars have been used. However these devices are costly and cumbersome and not particularly amenable to medical use as they may damage the adhesive by over-mixing.
Accordingly, in view of the foregoing there is believed to be a need for a mixing device capable of adequately mixing fast-setting multi-component adhesives without experiencing the clogging problems of prior art devices and a dispenser apparatus employing the same.